I've some questions about music quality on iTunes. I bought music throught iTunes and the format is *.m4a with a good quality sound. And I ripped some CD's at mp3@320kbps with good quality sound too. Now the problem is that for example, Coldplay Discography is about 3Gb @ 320kbps and I don't know if it's better to convert all my iTunes Library to AAC or I don't know if I could convert it to m4a to have all music with the best quality and the same format. What would you recommend to do? What is the best form to get the best quality and same format for all music? I'm tryind to organize all my library to transfer it to my iphone.